The present invention relates to a liquid coating composition or, more particularly, to an aqueous coating composition suitable for use to form a coating film on various kinds of electronic parts such as an oxygen-shielding coating film on various kinds of resist layers, coating film for preventing deposition of glass dust particles on liquid crystal display devices when the glass substrate thereof is cut for trimming, coating film for preventing degradation of the pattern configuration in a positive-working photoresist layer for the patterning irradiation with excimer laser beams and so on.
Liquid crystal display panels for exhibition of colored images are widely used in recent years in compact-size television sets, instrument panels on the dashboard of automobiles and airplanes and the like. According to this trend, the demand for color filters is rapidly growing as an essential part of liquid crystal color display panels. Known methods for the preparation of color filters include the dyeing method, printing method, pigment dispersion method and the like, of which the last mentioned pigment dispersion method is highlighted industrially in view of the economical advantage. This pigment dispersion method consists of the steps including formation of a light-shielding film on a substrate plate, coating thereof with a colored resist composition and an oxygen-shielding film and pattern-wise exposure thereof to light through a photomask followed by a development treatment, this sequence of steps being repeated three times for the respective primary colors of red, green and blue to form a three-colored patterned resist layer. While the most conventional material for the above mentioned oxygen-shielding film is a polyvinyl alcohol, the patterned resist layer formed by using a polyvinyl alcohol has a problem that the cross sectional profile of a line pattern has an inversely or upwardly broadening trapezoidal configuration so that, when an undercoat levelling layer or an insulating layer is formed on the patterned resist layer, an unfilled space is sometimes formed between the patterned resist layer and the undercoat levelling layer or the insulating layer eventually resulting in image line defects or incomplete electrical connection consequently to lead to a decrease in the quality of liquid crystal devices.